Process for improving the heat and acid resistance of cellulose-containing materials

ABSTRACT

An amino compound containing at least one primary amino group, a carbonyl compound containing at least one aldehyde or keto group and an isonitrile compound are applied to a cellulosic material and reacted thereon. The cellulosic material so modified has increased resistance to degradation from heat and acids and is suitable as an insulator in electrical devices.

- [45] Patented United States yatem [72] Inventors Heinrich Seibert Leverkusen; Peter Hofmann, Cologne-Stammheim; Ivar Ugi, Leverkusen-Schlebusch; Werner lllerzog, Vaihlngen; Karl Kemmner,

Unteremingen, all of Germany 121] Appl. No. 695,580 [22] Filed Jan. 4, 1968 Nov. 23, 1971 [73] Assignee Farbenfabrlken Bayer Aktiengesellschah Leverlkusen, Germany ["12] Priority Jan. 7, 1967 [33] Germany I 3 l I F 51195 [54] PROCESS FOR IMPROVING THE HEAT AND ACID RESISTANCE 0F CELLULOSE-CONTAINING MATERIALS 3 Claims, No Drawings [52] U.S.Cl 8/1l6.2, 8/1 16.4, 8/116.3, 8/120, 8/129, 252/63.7, 252/64, 317/259, 260/214, 260/231 [51] Int. Cl ..D06m13/l2, D06rn 13/38, D06m 13/54 [50] Field of Search 252/63.7,

OTHER REFERENCES Ugi, Angewandte Chemie, Vol. 74, pp. 9-22 (1962) Primary Examiner-George F. Lesmes Assislanl Examiner-J. Cannon AuorneyPlumley, Tyner & Sandt ABSTRACT: An amino compound containing at least one primary amino group, a carbonyl compound containing at least one aldehyde or keto group and an isonitrile compound are applied to a cellulosic material and reacted thereon. The cellulosic material so modified has increased resistance to degradation from heat and acids and is suitable as an insulator in electrical devices.

PROCESS FOR TMPROV G THE HEAT ACID IRESHSTANCE @IF CELLULQSE-CONTAWTNG MATERIALS As cellulose-containing materials which can be subjected to the process according to the invention the following may be mentioned, for example: cotton, cellulose, regenerated cellulose, cellulose derivatives, such as cellulose acetate, cellulose triacetate and cellulose ether, as well as paper, cardboard, woven and knitted fabrics and fleeces.

The amino compounds containing at least one primary amino group may belong to the aliphatic, cycloaliphatic, aromay be mentioned, ample: methylamine, n-butylamine, iso-butylamine, sec.-butylamine, tert.-butylarnine, allylamine, stearylamine, ethanolamine, propanolamine, S-dimethylaminopropylamine, N-(Y-aminopropyl)-morpholine, amino acetic acid ethyl ester, e-aminocaproic acid ethyl ester, benzylamine, cyclohexylamine, aniline, p-chloroaniline, 2-naphthylamine, 5- aminoquinoline, ethylene-diamine, hexamethylene-diamine, di-0,0-(y-aminopropyl)-1,4-butylene glycol, di-(yaminopropyl)-methylamine, 1,6,1 l-triamino-undecane, 1,4- diamino-cyclohexane, phenylene-diamine, diamino-toluene, 4,4'-diamino-diphenylmethane, polyethylene-imine dihydrazide and N,N-dimethyl-hydrazine.

The carbonyl compounds containing at least one aldehyde or keto group may also belong to the aliphatic, cycloaliphatic, aromatic or heterocyclic series; there may be mentioned, for example: formaldehyde, acetaldehyde, propionaldehyde, B glycidaldehyde, acrolein, polyacrolein, n-butyraldehyde, isobutyraldehyde, flhydroxy-butyraldehyde, -hydroxy-butyraldehyde, 2ethyl-2-hexenal-( l stearylaldehyde, cinnamaldehyde, hydrocinnamaldehyde, o-cyano-dihydrocinnamaldehyde, benzaldehyde, 2,4-dichlorobenzaldehyde, glutardialdehyde, a-hydroxy-adipic dialdehyde and dihydropyranaldehyde, further acetone, methyl ethyl ketone, methyl vinyl ketone, dipropyl ketone, ethylisoamyl ketone, S-methoxypentanone-( 2), methyLstearyl ketone, distearyl ketone, methyl-benzyl ketone, benzo-racemic acid ethyl ester, benzoracemic acid-N-cyclohexylamide, pevulinic acid ethyl ester cyclopentanone, cylohexanone, cyclododecanone, cyclododecadienone, acetophenone and benzophenone.

The isonitrile compounds also may belong to the aliphatic, cycloaliphatic, aromatic or heterocyclic series; the following may be mentioned, for example: ethylisonitrile, allylisonitrile, nand tert.-butylisonitrile as well as cyclohexylisonitrile, further N-(a-isocyanopropyl)-morpholine, benzylisonitrile, oand p-tolylisonitrile, 2,6-xylylisonitrile, azobenzene-4- isonitrile, hexanel ,6-diisonitrile, cyclohexanel ,4- diisonitrile, l,4-di-(isocyanaomethyl)-cylohexane, N-methyldi-(y-isocyanopropyl)-amine, N-cyclohexyl-di-(y-isocyanopropyl)-amine, N-rnethl-di-(B-isocyanofl -methylpropyl)-amine, di-(b-isocyanoethyl)-carbonate, di-(u-isocyano-b -methyl-propyl)-carbonate, di-0,0'-(-y-isocyano-b b dimethyl-propyl)-propanediol, 1,6,1 l-triisocyanoundecane, l l ,3-tri-('y-isocyanopropul)-indence, 4,4 -di-( isocyanomethyl)-diphenyl ether, l-methyl-3,5-diethyl benzene- 2,4-diisonitrile, 4,4-diisocyano-diphenylmethane, 2,4,4- triisocyano-diphenyl and 2,2-4,4-tetra-isocyano-diphenyl.

The three components, i.e., the amino compound, the carsolutions or emulsions in water or in organic solvents, such as methanol, methylene chloride, acetic acid ethyl ester, methyl glycol, benzene or mixtures thereof; emulsifiers, chiefly nonionic emulsifiers, such as nonylphenol polyglycol ether,

can also be used for the aqueous emulsions. Any sequence in which the three components are allowed to act may be chosen; in general, it is recommended to use the three components in admixture with one another.

instead of using the components amino compound and carbonyl compound by themselves, it is also possible to use them in the form of the aminals or Schifibases derived from these two components; there may be mentioned by way of example: urotropine, N,N',N'-trimethyl-hexahydrotriazine, imidazolidine, 1,l-di-(n-butylamino)-2-methylpropane, N- (methoxy-methyl)-benzylamine, N-butyl-butylidene-imine N- phenyl-benzylidene-imine, N-isobutyl-hexyidene-(Z)-imine and N-benzyl l -phenyl-ethylidene-imine.

The proportion between the total weight of the three components and the weight of the cellulose-containing materials may vary within wide limits. Suitable proportions can readily be determined by preliminary experiments; in general, it has been found sufficient when the total weight of the three components amounts to 2 to 30 percent of the weight of the cellulose-containing materials.

The treatment of the cellulose-containing materials with the 5 components to be used according to the invention can be effected by various methods, for example, by impregnating, dipping or spraying. Subsequently, the materials are expediently washed with water or organic solvents and dried at normal or elevated temperature.

The cellulose-containing materials treated according to the EXAMPLE 1 g. cellulose previously cleaned in conventional manner treatment with dilute sulfurous acid, are introduced into g. ethanol and treated with 2 g. stearylamine, lg. benzophenone as well as 1 g. cyclohexane-l,4-di-isonitrilc at 60 C. for 30 minutes, while stirring. The cellulose is then therefrom in conventional manner is eminently suitable as insulating material for electrotechnical purposes.

EXAMPLE 2 by treatment with dilute sulfurous acid, 100 methyl glycol, treated with a mixture of 1 g. aniline, l g. benzaldehyde and 2 g. azobenzene-4-isonitrile at 60 C. for 30 minutes, while stirring. The cellulose is then squeezed out and subsequently washed first with methyl glycol and thereafter with acetone. The paper obtained therefrom in conventional manner is likewise eminently suitable as insulating material for electrotechnical purposes,

EXAMPLE 3 100 g. cellulose previously cleaned in conventional manner by treatment with dilute sulfurous acid, are introduced into 100 g. water, stirred into a mixture of 2 cc. concentrated ammonia, 2 cc. 30 percent formaldehyde and 1.5 g. N-methyl-di- ('y-isocyanopropyl)-amine and allowed to stand at room temperature for 18 hours. The cellulose is then squeezed out and washed with water. Paper produced from the cellulose thus treated in conventional manner, is likewise eminently suitable as insulating material for electrotechnical purposes.

EXAMPLE 4 Unsized paper prepared from a cellulose which was cleaned in conventional manner by the treatment with dilute sulfurous acid, is impregnated on the size press with an aqueous solution containing a mixture of ethanolamine, 30 percent femaldehyde and N-methyl-di-(yisocyanopropyl)-amine in a proportion by weight 1:1:3, followed by drying in the paper machine. About 20 g. of the above mixture are allowed to act upon 1 kg. of paper; the concentration of the solution is then adjusted to the operating velocity of the paper machine and 

2. Cellulose-containing materials treated according to the process of claim
 1. 3. As an electrotechnical insulating material, a cellulose-containing material modified by the process of claim
 1. 